Webmail (Horde) sidebar.php is not loading

Issue: The sidebar.php file in the horde webmail is not loading. (ie. It is asking for download)
Check whether the value is "$conf['compress_pages'] = true;" in /usr/share/psa-horde/config/conf.
php

If it is, then check the log file /var/log/httpd/error_log. This will look like following:
Allowed memory size of 8388608 bytes exhausted (tried to allocate 16 bytes)
Allowed memory size of 8388608 bytes exhausted (tried to allocate 16 bytes)

Modify the value of post_max_size in the php.ini to 32M. (The default value will be 8M)
post_max_size = 32M

Restart the apache (/etc/init.d/httpd restart)

This will fix the issue.